The present invention relates to substituted sulfonamide compounds, processes for the preparation thereof, pharmaceutical compositions containing these compounds, and the use of such substituted sulfonamide compounds in pharmaceutical compositions for treatment or inhibition of pain and/or other conditions at least partially mediated by the bradykinin 1 receptor.
In contrast to the constitutive expression of the bradykinin 2 receptor (B2R), in most tissues the bradykinin 1 receptor (B1R) is not expressed or expressed only weakly. Nevertheless, expression of B1R can be induced on various cells. For example, in the course of inflammation reactions a rapid and pronounced induction of B1R takes place on neuronal cells, but also various peripheral cells, such as fibroblasts, endothelial cells, granulocytes, macrophages and lymphocytes. In the course of inflammation reactions, a switch from a B2R to a B1R dominance thus occurs on the cells involved. The cytokines interleukin-1 (IL-1) and tumour necrosis factor alpha (TNFα) are involved to a considerable degree in this upwards regulation of BIR (Passos et al. J. Immunol. 2004, 172, 1839-1847). After activation with specific ligands, B1R-expressing cells then themselves can secrete inflammation-promoting cytokines such as IL-6 and IL-8 (Hayashi et al., Eur. Respir. J. 2000, 16,452-458). This leads to inwards migration of further inflammation cells, e.g. neutrophilic granulocytes (Pesquero et al., PNAS 2000, 97, 8140-8145). The bradykinin B1R system can contribute towards chronification of diseases via these mechanisms. This is demonstrated by a large number of animal studies (overviews in Leeb-Lundberg et al., Pharmacol. Rev. 2005, 57, 27-77 und Pesquero et al., Biol. Chem. 2006, 387, 119-126). On humans too, an enhanced expression of B1R, e.g. on enterocytes and macrophages in the affected tissue of patients with inflammatory intestinal diseases (Stadnicki et al., Am. J. Physiol. Gastrointest. Liver Physiol. 2005, 289, G361-366) or on T lymphocytes of patients with multiple sclerosis (Pratet et al., Neurology. 1999; 53, 2087-2092) or an activation of the bradykinin B2R-B1R system in the course of infections with Staphylococcus aureus (Bengtson et al., Blood 2006, 108, 2055-2063) is found. Infections with Staphylococcus aureus are responsible for syndromes such as superficial infections of the skin up to septic shock.
Based on the described pathophysiological relationships, there is a great therapeutic potential for the use of B1R antagonists on acute and, in particular, chronically inflammatory diseases. These include diseases of the respiratory tract (bronchial asthma, allergies, COPD/chronic obstructive pulmonary disease, cystic fibrosis etc.), inflammatory intestinal diseases (ulcerative colitis, CD/Crohn's disease etc.), neurological diseases (multiple sclerosis, neurodegeneration etc.), inflammations of the skin (atopic dermatitis, psoriasis, bacterial infections etc.) and mucous membranes (Behcet's disease, pelvitis, prostatitis etc.), rheumatic diseases (rheumatoid arthritis, osteoarthritis etc.), septic shock and reperfusion syndrome (following cardiac infarction, stroke).
The bradykinin receptor system is moreover also involved in regulation of angiogenesis and has potential as an angiogenesis inhibitor in cancer cases and macular degeneration on the eye. B1R knockout mice also are protected from induction of obesity by a particularly fat-rich diet (Pesquero et al., Biol. Chem. 2006, 387, 119-126). B1R antagonists are therefore also suitable for treatment of obesity.
B1R antagonists are suitable in particular for treatment of pain, in particular inflammation pain and neuropathic pain (Calixto et al., Br. J. Pharmacol. 2004, 1-16), and here in particular diabetic neuropathy (Gabra et al., Biol. Chem. 2006, 387, 127-143). They are furthermore suitable for treatment of migraine.
In the development of B1R modulators, however, there is the problem that the human and the rat B1R receptor differ so widely that many compounds which are good B1R modulators on the human receptor have only a poor or no affinity for the rat receptor. This makes pharmacological studies on animals considerably difficult, since many studies are usually conducted on the rat. However, if no activity exists on the rat receptor, neither the action nor side effects can be investigated on the rat. This has already led to transgenic animals with human B1 receptors being produced for pharmacological studies on animals (Hess et al., Biol. Chem. 2006; 387(2):195-201). Working with transgenic animals, however, is more expensive than working with the unmodified animals. Since in the development of pharmaceutical compositions, however, precisely long-term toxicity studies on the rat belong to the standard studies, but this is inappropriate in the event of an absence of activity on the receptor, an important established instrument for checking safety is lacking for the development of such compounds. There is therefore a need for novel B1R modulators, B1R modulators which bind both to the rat receptor and to the human receptor offering particular advantages.